Archbishop Hector Aguer of La Plata, Argentina warned that society is gravely harmed when those in positions of authority engage in lying.

"St. Thomas Aquinas taught that people could not live together without mutual trust and without living in the truth," Archbishop Aguer said in his program Keys to a Better World.  

"In other words, lying, when done on a massive scale and when done by somebody in a position of great responsibility, causes harm to our life together and is disastrous for all of society," he explained.

"I think of cases involving people, for example, priests, politicians, especially those in government, journalists or manages or owners of media outlets, who have more responsibility towards those around them, because they cause great harm," the archbishop said.

Truth is a value that should not be betrayed, and according to Christian morality, lying "is evil by its very nature."  

"Jesus says the devil is a liar and the father of lies," he said.

Archbishop Aguer also argued that there are no such things as white lies. While lying is not always a mortal sin, he noted, white lies do not exist because whenever we lie "we are skirting the need to convey the truth."

"It is true that a lie does not always have the same degree of gravity and sinfulness," he continued.  

"Some lies are grave and others are less serious, it depends on the nature of the truth that is in question, the truth that is being betrayed by lies, and it also depends on the harm that comes from telling a lie," the archbishop explained.

"We are always responsible for the lies we tell and we have the obligation to repair the harm our lies cause.  Why do I bring this up? Because I think that in Argentinean society there is a strong tendency to bend the truth," he said.

Archbishop Aguer said such a tendency would be difficult to reverse if it becomes a cultural habit. "I think we need to begin by upholding the truth and telling the truth in our everyday relationships.  

We don't have to lie just because we think it is a white lie, because when we do that we are tricking the person with whom we are talking. It is in those small things every day that we strengthen the beautiful Christian virtue of truthfulness," he said.